Air compressor



May 19, 1925. I 1,538,716

. W. L. MARTIN AIR COMPRESSOR Filed Nov; 25, 1922 5 Sheets-Sheet 1 WT T ATTORNEY ffdJ/ mw WITNESSES May 19, 1925.

w. L, MARTIN AIR COMPRESSOR Filed Nov. 25. .1922

5 Sheets-Sheet 2 INVENTOR WL.MaJrZz'n lfdJ/limwo ATTORNEY WITNESSES lNVENTOR WL.Mar tin ATTORN EY WITNESSES May 19, 1925.

w. L. MARTIN AIR COMPRESSOR Filed Nov. 25. 1922 5 Sheets-Sheet 4 WL.MarZz/'n ATTORNEY WITNESS May 19, 1925. 1,538,716

w. L. MARTIN AIR COMPRESSOR Filed Nov. 25. 1922 5 sums-sheet 5 wll'Ma/ria'n, MENTOR WITNESSS Patented May 19, 1925.

NTITJED YSTATEIS WILLIAM L. MARTIN, or STAMFORD, TEXAS.

AIR GOMI'RESSOR.

"Application filed November 25, 1922. "serial No. 603,257.

1 0 all whom it may concern Be it'known that 1, WILLIAM L. MARTIN, a citizen'of the United States, residing at Stamford, in thecounty of Jones and State of Texas, haveinvented new a'nduseful 11nprovements in Air Compressors, of which the following is a specification.

This invention relates to an air compressor, the general object of the invention being to locate the compressor in an air tank which willreceive the air compressed by-thc device and the compressed air in which will facilitate the operation of the compressor.

Another object of the invention is to provide means for preventing the compressed air from the tank from interfering with the suction stroke of the compressor.

This invention also consists in certain other features of construction and in the combination and arrangement of the several parts, to be hereinafter fullydescribed,-illustrated in the accompanying drawings and specifically pointed out in the appended claims.

In describing my invention in detail, reference will be had to the accompanying drawings wherein like characters denote like or corresponding parts throughout the several views, and'in which Figure 1 is a side view of the invention showing-a vertical section of the tank.

Figure 2 is a similar view but showing the parts in a difierent position.

Figure 3 is a plan 'view with parts broken away.

Figure l is a "section on line 44of F igure 1.

Figure 5 is a section on line 5-5-of Fig ure 1.

Figure'G is. a longitudinal sectional view through the cylinder.

Figure 7 is a transverse sectional view through the depending part of one of the piston supports.

Figure 8 is a transverse sectional view through the cylinder.

Figure 9 is an enlarged View of one of the adjusting members for the piston supports.

Figure 10 is a View of one ofthe piston supports.

Figure 11 is a side view of Figure 9;

I Figure 12 is a front view of the lower end of the depending part of one of the piston supports.

In these views 1 indicates a tank which is constructed so that it will contain air. A

cylinder 2is arrangedin said tank ina vertical position and thiscylinder has an inlet valve 3 which connects the bottom of [the cylinder with the atmosphere when the valve isopen and has an outlet port 4 which con nects the cylinder withtheinte'rior of the tank. The valve 3 will open onthe upstroke-and the valve4 will' open on'the down stroke of the piston 5. In actual practice there would=be "a'sec'ond oylinder at the top of the tank with its piston arranged "to operate alternately with the 'piston 5 but tin order to avoid confusion this second cylinder is omitted from the drawings. Vertical guideways 6 are arranged in the tank at each "side thereof and these guideways are engaged by the ends -of a pin '7 which is carried bythe piston and which has rollers 8thereon for a purpose tobe hereinafter described. The pinis of squareshape in cross section and engages the square hole 9 in the piston 5. These-g'uidewayscause the piston to move in a vertical plane. Theuppe'r end of the piston is inclined and it has a plate 10 of polished steel thereon which is movably held by theclamping plates 11 which are connected with the piston body by the Y frame carries an vinclinedplate 18of pol-- ished steel and which forms a slide for the head of the piston, the ends of the plate being suitably secured *to the ends of the frame. A piston support 19is pivotally secured to the front-end of the frame ateach side thereof, said support consisting of a long bar 19 which is pivoted at itsfront end to the frame, a short supporting strip 19 and'a short bar 19' which is arranged parallel with the rear part of the bar '19, and which is secured to the upperend of the strip 19 above the bar 19-. Awheel 20 is carried bythe rear end of the'piston support and this wheel is adapted to engage a short rail 21 at the rear end of the tank which is provided with an inclined front end. These wheels and rails willactto hold the piston supports in raised position when the frame is at the rear of its stroke. A plate 22 is secured to each strip 19 and said plate has a recess 23 therein in which is slidably mounted a pin carrying member 24, the stem 25 of which has a spring 26 thereon for holding the member in its lowest P081 tion. The member is held in the recess by the strips 27 and its pin is shown at 28. The piston supports are adjusted by means of the rocking members 29, each of which is pivotally secured to the rear end of the. frame and which consists of the cam head having a guideway 30 therein and a stem 31. which extends below the pivot point of the member. Pins 32 on the frame limit the rocking movement of the member 29 and a rail 33 is suitably supported in the tank at each side thereof and is adapted to actuatesaid member. Each rail carries spring pressed buttons 34 at its ends which act to reverse the member 29 at the ends of its movement.

From the above it will be seen that the reciprocation of the frame will cause the piston to reciprocate vertically in its cylinder so as to first draw in air in the cylinder from the exterior of the tank and then discharge the air into the tank. Onthe forward stroke of the frame the rollers 8 engaging the bars 19 of the supports 19 will impart the up stroke to the piston and during this action the head of the piston will be pressed firmly against the bottom of the slide so as to prevent air in the tank from acting on the head of the piston. The lower wall of the groove 30 in the cam head is so formed that the lower end of the strip 19 of each piston support 19 will rest thereon when the member 29 is in engagement with either of the stop pins 32 and the pin 28 has left the groove 30. The front end of this wall will support the strip 19" in its lowest position and the rear end will support it in its highest position so that when the members 29 are tilted towards the front, as shown in Fig. 9, the piston supports 19 will be in raised position so as to force'the upper end of the piston against the plate 18 and when said members 29 are in the reverse position from that shown in Figure 9, the piston supports are held in their lowest position with the end of the piston spaced from the plate 18. Near the end of theforward stroke the stem 31 of each member 29 will pass over the forward button 84 which will move downwardly to permit the stem to pass and then the button will be forced upwardly by its spring so that at the beginning of the back stroke the stem will encounter this button and thus the member 29 Will be rotated on its pivot and as it turns it catches the pin 28 and thus moves the rear end of the piston support 19 downwardly. At the end of the movement of the member 29 the pin is released but said member 29 will still engage the lower end of the strip 19 and thus act to hold each support 19 in lowered position. As the endsof the pin 7 of the piston are located between the bars 19 and 19 of the piston supports 19 the piston will be moved downwardly slightly as the piston supports are pulled down so as to space its head from the slide 18 and thus permit the compressed air in the tank to act on the head. As the frame moves rearwardly the piston descends forcing air from the cylinder into the tank. Before the frame reaches its rearward position the wheels 20 will engage the rails 21, thus raising the piston supports 19 again which will force the piston head against the slide 18. Just before the frame reaches the end of its back stroke the stem 31 of each member 29 passes over the rear button34 which springs back into place behind the stem ready to reverse the member 29 again at the beginning of the forward stroke of the frame. When the member 29 is reversed at the beginning of the forward stroke the pin 28 will be engaged by the top of the head of the member 29 so that the member 24: will be raised against the action of its spring and as soon as the member 29 passes from under the pin the parts will be returned to lowered position again by the spring 26.

The slide is set in frame at an angle of 30 degrees or as 3 is to 1.

Only one piston is against the slide at a time or practically so, because as one is being pulled out of its cylinder and held air tight against the slide the other is released from the slide and is going into its cylinder.

On each stroke of the frame as a piston is being pulled out of its cylinder and held air tight against the slide the only resistance to overcome is the friction for the following reasons:

When the piston head is pressed air tight against the slide it becomes to all intent a part of the slide and the slide assumes the pressure that would be on the piston head. We know that the pressure exerted on a surface by a gas is always perpendicular to that surface. Then by resolving the force on the top of that part of the slide which covers the piston into its component parts we have a certain component pressing in a horizontal direction and a certain component in a vertical direction. In this device it is 3 to 1,tl1at is, for

every pound horizontal pressure there is undersurface of the slide there is more pressure on the top of the slide than on the bottom of it and this difference of pressure is on the top of that part of the slide which covers the piston. Now, as the top of the piston is inclined the rear of the piston is longer than the front. sure on the rear of the-piston than there is on the front and this difference of pressure is in a horizontal direction and counteracts the horizontal component part on top of that part of slide which covers piston. Therefore, the only resistance to overcome on forward stroke is that due to the vertical component part of the pressure on the top of that part of slide which covers the piston plus the weight of the frame with its parts which rolls on the horizontal rail 15, so there is no resistance to overcome but the friction.

The other and main advantage of the compressor is this, after several strokes of the frame have been made and the pressure in tank raised, we have the advantage of this pressure on the piston head as soon as it disengages the slide on the back stroke, because the piston is resting on the supports which are fastened to the frame parallel to the slide, having the same thirty degree incline. Therefore this pressure on piston which rests on supports which in turn are fastened to frame will have a three to one pressure on frame, one part will be in a horizontal direction and three parts in a perpendicular direction. The one part horizontal pressure will be pushing the frame back so the piston can descend into cylinder. For example, suppose we have a forty pound pressure in tank, that is forty pounds to the square inch and area of piston head is ten inches. Then as soon as piston disengages slide on back stroke we will have four hundred pounds pressure on top of piston head. Now as stated above, the piston rests on the supports which in turn are fastened to frame parallel to slide having the same thirty degree incline as slide. Therefore, this pressure or weight on supports caused by pressure on piston will be bearing or pressing on supports, which are fastened to frame as stated above, one hundred poundsin a horizontal direction and three hundred pounds in a perpendicular direction. The hundred pounds will be helping to push the frame on its back stroke.

This one hundred pounds, however, will not push on the supports the entire stroke. The advantage of it gets less as the frame moves back and as soon as the air pressure in the cylinder, as the piston descends, becomes equal to that in the tank, we lose this force or advantage on this stroke. However, the greater the pressure is in the tank the greater is this advantage, and nearer it helps to push the entire stroke.

It is thought from the foregoing descrip- Therefore, there is more pres t-ion that the advantages and novel features of my invention will be readily apparent;

I desire it to be understood that I may make changes in the-construction and in the combination and arrangement of the several parts, provided that such changes fall within the scope of the appended claims.

1. A device of the class described comprising a tank, a compressor therein having its inlet in communication with the atmosphere, a reciprocating member in the tank, means for reciprocating the same and means carried by said member for reciprocating the piston of the compressor.

2. An apparatus of the class described comprising a tank, a compressor therein having its inlet port communicating with the atmosphere and its outlet port with the interior of the tank, a reciprocating frame in the tank, means for reciprocating the frame, means carried by the frame for moving the piston of the compressor on its suction stroke and for releasing the piston on its expelling stroke.

3. An apparatus of the class described comprising a tank, a compressor therein having its inlet port in communication with the atmosphere and its outlet port in communi cation with the interior of the tank, the piston of the compressor having an inclined head, a reciprocating frame in the tank, means for reciprocating the same, an inclined slide carried by the frame for engaging the inclined head of the piston, a piston support movably carried by the frame and means for holding the support in a position to cause the head of the piston to engage the slide on the suction stroke and to move the support to space the head of the piston from the slide on the expelling stroke.

4. An apparatus of the class described comprising a tank, a compressor therein hav ing its inlet port in communication with the atmosphere and its outlet port in communication with the interior of the tank, the pis-' ton of the compressor having an inclined head, a reciprocating frame in the tank, means for reciprocating the same, an inclined slide carried by the frame for engaging the inclined head of the piston, a piston support movably carried by the frame, means for holding the support in a position to cause the head of the piston to engage the slide on the suction stroke and to move the support to space the head of the piston from the slide on the expelling stroke, such means consisting of a rocking member adapted to engage a part of the piston support and means for actuating said member near the end of each stroke of the frame.

5. An apparatus of the class described comprising a tank, an air compressor located therein and having its 'inlet port communicating with the atmosphere and an exhaust port communicating with the interior of the lowering the support at the beginning of tank, guideways in the tank, aframe mountthe back stroke of the frame for spacing the 10 ed to slide in said guideways, means for rehead of the piston fromthe slide and means ciproeating the frame, an inclined slide 'carfor raising the support at the beginning of ried by the frame, the head of the piston the forward stroke.

being inclined to engage the slide, an in- Intestimony whereof I affix my signm elined piston support pivoted at one end of ture.

the frame, means carried by the frame for I WILLIAM L. MARTIN. 

